The image of Sirius A and Sirius B taken by the Hubble Space Telescope. The white dwarf can be seen to the lower left.[79] The diffraction spikes and concentric rings are instrumental effects.
With an apparent magnitude of −1.46, Sirius is the brightest star system in the night sky, almost twice the brightness of the second brightest star, Canopus.[80] However, it is not as bright as the Moon, Venus, or Jupiter; at times, Mercury and Mars are also brighter than Sirius.[81] Sirius can be seen from almost everywhere on the Earth's surface, with only observers north of 73 degrees latitude unable to see it, and it does not rise very high when viewed from some northern cities, reaching only 13° above the horizon from Saint Petersburg.[82] Sirius, along with Procyon and Betelgeuse, forms one of the three vertices of the Winter Triangle to observers in theNorthern Hemisphere.[83] Due to its declination of roughly −17°, Sirius is a circumpolar star from latitudes south of 73° S. From theSouthern Hemisphere in early July, Sirius can be seen in both the evening where it sets after the Sun, and in the morning where it rises before the Sun.[84] Due to precession (and slight proper motion), Sirius will move further south in the future. Starting in the year 9000,